Strategies to slow cabbage from bolting
“Let death take me planting my cabbages, indifferent to him, and still less of my gardens not being finished.”
— Michel de Montaigne, “The Complete Essays,” 1572
Known as the father of modern skepticism, Michel de Montaigne (1532-1592) was one of the most influential writers of the French Renaissance. His talent for probing intellectual topics through personal storytelling helped to popularize the essay as a literary genre.
Whenever gardeners shrug in exasperation and utter “What do I know?” about some unexpected occurrence in the garden, we have Monsieur Montaigne to thank, because he was first to use the sarcastic expression almost 450 years ago.
I used his turn of phrase (along with less literary expletives) recently when I discovered that my Chinese cabbage had bolted. Seemingly overnight, a thick stem appeared in the center of each plant, topped with a deceptively cheerful yellow flower. This flower did not make me happy, though. Its yellow was a cautionary signal that my cabbage was going to seed and no longer flavorful for harvesting.
Cabbage is a cool-season crop, so I suppose I shouldn’t be surprised that my Chinese cabbage flowered. I thought I would be harvesting my cabbage until the end of June, but what do I know?
As it turns out, Chinese cabbage — particularly the heading Napa type — is susceptible to spring bolting, as are other kinds of cabbages and plants in the Brassica family, and lettuce, basil, carrots, turnips, spinach, celery and onions.
Bolting is the plant’s way of saying “I’m done” in terms of producing edible leaves, stems and roots. The plant senses its life is coming to an end, so it refocuses its last bit of energy on producing seeds in order to perpetuate the species.
Chinese cabbages are especially sensitive to temperature shifts and the lengthening days. They don’t fare well when exposed to excessive sunlight and heat.
Hot weather is usually the cabbage’s trigger for bolting, but sudden exposure to low temperatures at night may also cause plants to go to seed. A lack of moisture or nutrients are other potential stressors.
Once plants have begun to bolt, there’s no way to stop the process. If Chinese cabbages are detected in early stages of bolting, the flower and stalk may be snipped off to buy a few extra days of harvesting. Even if the flower is removed, the edible leaves, stems and roots soon turn tough and bitter.
Here are a dozen strategies to prevent Chinese cabbages from bolting:
Reduce plant stressors by watering regularly and adding nutrient-rich compost to soil.
Healthy cabbage needs adequate amounts of phosphorous and calcium in the soil. Add these nutrients with fish emulsion or liquid seaweed after the plants are established.
Use floating row cover to protect plants from excessive sunlight/heat and low temperatures at night.
Provide a bit of shade by planting cabbage close to tall plants, tomato cages or trellised plants.
Use mulch around plants to keep the ground temperature stable and to retain moisture.
Plant spring crops earlier by starting indoors and using row tunnels outdoors so cabbage is well established before hot weather arrives.
Wait until fall to plant cabbage when the chances for bolting are lower.
Plant Michihili and loose-leaf cabbages rather than heading types. The OSU Extension Service recommends Jade Pagoda for our area.
Use cabbage seeds that are offspring from plants grown in local conditions. Siskiyou Seeds, for example, sells Maruba Santoh, China Choy and Nozaki Early Chinese cabbages grown at Seven Seeds Farm in Williams.
Grow bolt-resistant Chinese cabbage varieties, particularly for spring plantings. Territorial Seeds offers China Express, a Napa cabbage type that has shown resistance to bolting.
Plant Chinese cabbage varieties that are quick to mature. Soloist is a baby Chinese cabbage that is ready to harvest in 40-50 days (most cabbages require 70-80 days).
Practice “cut and come again.” This means picking off outer leaves of the cabbage as you need them, similar to harvesting loose-leaf lettuce. This practice spurs the cabbage to continue producing leaves, rather than flowers.
Still, just as garden hoses are destined to kink, some of our Chinese cabbages or other garden vegetable plants will inevitably bolt. When this happens, snip the flowers off and use them for a garnish. Harvest the cabbage as soon as possible and stir-fry with seasoning to offset the bitterness. Collect the seeds and try growing it again.
Or shrug and say, “What do I know?” about growing Chinese cabbage, and plant something else.
Rhonda Nowak is a Rogue Valley gardener, teacher and writer. Email her at Rnowak39@gmail.com. For more about gardening, visit her blog at http://blogs.esouthernoregon.com/theliterarygardener/ and listen to her podcasts at https://mailtribune.com/podcasts/the-literary-gardener.